1. Field of the Invention
The present invention relates to a toggle type punch driving system to be mounted in a punch press.
2. Prior Art
Heretofore, a crank type mechanical punch press has been used as a punch driving system with a ram for vertical movement, wherein the lower end of a pitman arm connected to a crank shaft is connected to the ram.
According to such conventional mechanism, a single up-and-down movement of the ram is performed by one rotation of the crank shaft. Therefore, in order to shorten the machining time by high-speed punching, it is necessary to increase the rotating speed of the crank shaft. However, the rotating speed of the crank shaft is restricted by the rotating speed of a motor, bearing performance, etc. and it is difficult to increase the punching speed.